Cloth holding means for tenters



F. B. MORRILL 2,787,822

CLOTH HOLDING MEANS FOR TENTERS April 9, 1957 Filed Oct. 5, 1955 2 Shets-Sheet 1 3% f a 1' if p90 k R INVENTOR.

' FRANK B. Momau.

BY I QM M W HTTOPNEYS April 9, 1957 F. B. MORRILL CLOTH HOLDING MEANS FOR TENTERS Filed Oct. 5, 1955 2 Sheets-Sheet 2 /ne ---/Zb INVENTOR.

'1" FRANK} B. MORRILL Unite States Patent CLOTH HOLDING MEANS FOR TENTERS Frank B. Morrill, North Adams, Mass., assignor to James Hunter Machine Company, North Adams, Mass, a corporation of Massachusetts Application October 5, 1955, Serial No. 538,701

Claims. (CI. 26-62) This invention relates to tenters in which a fabric to be dried or otherwise treated is drawn through the treating Zone while gripped at its side edge portions or selvages and held in transversely stretched condition. The invention has particular reference to an improved tenter of the type in which the fabric is gripped at its selvages by tenter pins on which the fabric is impaled.

ln tentering machines of the pin type, as commonly made heretofore, the fabric is held by two endless chains each having upright pins on which the selvage edges of the fabric are impaled. These chains are movable on respective tracks extending from a loading station, where the selvage edges of the fabric are placed upon the pins (as by means of brushes or pressure wheels well known in the art), to a stripping station at the other end of the machine, where the fabric, after drying or other treating, is removed from the pins. At the loading station or entrance to the machine, the tracks and chains are relatively close together, so that the selvage edges of the fabric can be conveniently placed upon the pins. From this loading station the tracks (and, therefore, the chains) diverge from each other so as to stretch the fabric to the requisite width for the drying or tentering operation.

.It is the conventional practice in tentering machines of this type to mount the tenter pins on plates fixed to the chain links and from which the pins extend upward at a fixed angle to the vertical, so that the pins on each chain extend upward in diverging relation to the pins on the opposing chain. By virtue of this fixed angle of the pins (which is usually in the order of to the vertical), and their diverging relation to the pins on the opposing chain, the fabric is held more securely on the pins and is less apt to be lifted off the pins, as by a greater pressure of the drying medium on the lower surface of the fabric than on the upper surface during travel of the fabric through the drying chamber. However, even with this arrangement of the tenter pins, the fabric will sometimes be lifted from the pins before reaching the stripping station, particularly if there should be substantial slack in the fabric in the transverse direction. On the other hand, it is not feasible to increase the fixed angle of the pins beyond about 20 to the vertical because the operations of impaling the fabric on the pins at the loadingstation and stripping the fabric from the pins at the unloading station would then be too diificult or impossible.

The present invention has for its principal object the provision of a pin type of tenter which overcomes the above-mentioned difficulties heretofore experienced in prior machines of this type.

A tenter made according to the invention comprises a pair of tracksand endless tenter chains movable on the tracks for drawing the fabric therealong from a fabric loading station to a fabric stripping station. These chains include links each of which has a lever pivoted on the link for swinging movement about an axis substantially parallel to the corresponding track. The lever ice extends inward from its axis toward the opposing chain, the'lever axis preferably being a pivot mounted on an inwardly extending arm of the link. At its inner portion, the lever carries upwardly extending tenter pins adapted to pierce the selvage of the fabric. A stop fixed relative to the link is engageable with the lever to limit downward movement of the tenter pins. The lever when engaged with this stop is in a fabric loading position wherein the upwardly extending pins are at a minimum angle to the vertical (for example, as little as 0 but preferably in the order of 20) and the base portions of the pins are located below the horizontal level of the lever axis. However, the lever is adapted to swing away from the stop to permit raising of the pins, whereby the latter assume a greater angle to the vertical while diverging from the upwardly extending pins of the opposing chain. Cam means are fixed relative to each track at the loading and stripping stations and are engageable with the lever on the moving chain to force the lever against the stop, whereby the tenter pins are held at the minimum angle to the vertical during the operations of placing the fabric selvage on the pins and stripping the selvage from the plus.

With this construction, the fabric can be impaled on and stripped from the tenter pins in the usual manner at the entrance and discharge ends of the machine, since the pins at these points are held by the cam means at the minimum angle to the vertical to facilitate these operations. However, as the fabric moves from the loading station toward the stripping station, the pins are free to swing upward about the pivot of the lever on which the pins are mounted, whereby the pins tilt away from the vertical and from the pins on the opposing chain and therefore hold the fabric more securely against upward displacement from the pins. More particularly, as the chains progress from the loading station into the dryer and along the diverging portions of the chain tracks, the chains exert transverse or weft tension on the fabric; and due to the fact that the horizontal level of the lever axis is above the base portions of the pins when the latter are in their lowermost or fabric-loading position, this increased tension acts through the pins to pull the inner portion of the pin carrying lever upward about the lever axis to a position where the pins will have a substantially greater angle to the vertical (for example, 40). If the velocity or pressure of the drying medium is greater on the lower surface of the fabric than on its upper surface, the fabric will be blown upward; but the pins are free to move upward with the fabric on the lever, this upward movement resulting in a still greater angle of the pins relative to the vertical. In other words, the tenter pins, by virtue of their location on the lever, will automatically adiust themselves to the weft tension in the fabric and to upward or downward movement of the fabric incident to unequal pressures on its upper and lower surfaces and throughout this range of movement of the pins, they diverge at a substantially greater angle to the vertical (and from the pins on the opposing chain) than is the case when the pins are at the fabric loading and fabric stripping stations, whereby the fabric is held more securely on the pins.

When the pressure is greater on the upper surface of the fabric than on its lower surface, the fabric will, of course, tend to move downward and pull the pins downward so as to force the lever against the stop. This aetion, however, can be prevented by providing additional cam means engageable with the lever to prevent the pins from moving below a certain height somewhat above the stopped position of the lever, so that the pins cannot return to their minimum angle relative to the vertical, such supplemental cam means being located along the pori atented Apr. 9, 1957 tions of the tracks intermediate the loading and stripping stations.

For a better understanding of the invention, reference may be had to the accompanying drawings, in which Fig. l is a tranverse sectional view of one of the chains of a tenter embodying a preferred form of the invention, showing one of the chain links and the cam means for operating the pin-carrying lever;

Fig. 2 is an elevational view of the chain link, as seen from the left in Fig. 1;

Fig. 3 is a plan view of the chain link without the pincarrying lever;

Fig. 4 is a plan view of the chain link lever without the pins, and

Fig. 5 is a schematic plan view of the tenter, showing the location of the cam means for operating the pin carrying levers of the tenter chains.

Referring to the drawings, the reference numeral (Fig. 1) designates the base of one of the two tracks. Extending along the inner edge portion of the base 10 is a vertical guide plate 10a, which faces a corresponding guide plate (not shown) extending along the inner edge of the opposing track. Each track 10 supports an endless chain comprising links 11. As shown in Figs. 14, each chain link 11 is provided at one end with jaws 11a forming a clevis, and at the other end with a reduced portion or tongue 11b. The tongue 11b of each link is adapted to fit closely between the jaws 11a of the next link, to which the tongue is hinged by a pivot pin (not shown) extending through holes lie in the clevis jaws and an aligned hole 11a in the tongue, as is conventional in the art. Thus, a series of the links 11,- pivotally connected end to end, forms an endless chain of which the upper section is adapted to ride along the corrcsponding track 10 where it is guided by the inner plate 10a of the track. Upward displacement of the chain from the track 1% is prevented by means of upper plate 1% overlying the track and secured thereto in any suitable manner (not shown). A lateral arm 11a is rigidly connected to the link 11 and extends inward between the upper plate tub and the top of guide plate 10 toward the opposing chain of the tenter.

A lever or swinging plate 12 is pivotally mounted on the inner portion of the link arm 11c, as by means of a pivot pin 13 extending generally parallel to the track 10 and the chain thereon, which is made up of the links 11. As best shown in Figs. 3 and 4, the link arm 11a is forked at its inner portion and the two prongs of the fork are form-2d with aligned openings 11f; while the lever 12 is provided at its outer portion with three prongs between which the prongs of the arm 11c are adapted to fit. The three prongs of the lever 12 are formed with aligned opening 12a, and the pivot pin 13 (Fig. 1) extends through the aligned openings 12:: and 11). At its inner portion, the lever 12 carries a pin plate 14 mounted on top of the lever and releasably secured thereto by machine screws 15. These screws extend loosely through holes 12b in the lever 12 and are screwed into threaded holes in the pin plate 14. Tenter pins 14a are secured at their base portions in the pin plate 14 and extend upward therefrom. These pins form a row extending along the pin plate i4 substantially parallel to the pivot 13 and the track 10.

The central prong of the lever 12, which is shown at 12c. forms a lug extending under the link arm 11a. At its upper portion, the lug 12c is engage'able with a set 16 threaded in the overlying link and 11a. As shown in Fig. l, the inner portion of lever 12 exerts a substantially greater turning moment on the lever than its outer por tion, including the lug 120, so that the lever tends to turn counter-clockwise on its pivot 13. However, the set screw 16, by engagement with the lug 12c, limits this turning of the lever; and when the lug is engaged with the set screw 16, the lever is held in a fabric loading position wherein the pin plate 14 is located a substantial distance 4t. below the horizontal level of the axis of the pivot pin 13. In this position of the lever, the upwardly extending pins 14a diverge from the vertical at an angle of about 20 and also diverge from the corresponding pins of the chain on the opposing track 10.

During the operations of placing the fabric on the pins 14a and stripping the fabric from the pins, the lever 12 is positively held by cam means 17 in the position shown in full lines in Fig. 1, wherein the pins diverge at a minimum angle (about 20) from the vertical. The cam means 17,,as shown in Fig. 1, comprise a cam 17 secured to the track 10, as by machine screws 17a, and extending parallel to the track below the lug 12c. As the chain link 11 moves to the loading station L of the tenter (Fig. 5), the lug 12c engages the corresponding cam 17 at the loading station and is held by this cam against the overlying set screw 16, so that the adjacent selvage of the fabric F can be impaled upon the tenter chains 14a in the usual manner, as by means of conventional brushes (not shown). Similarly, when the link 11 reaches the stripping station S of the tenter (Fig. 5 another cam 17, fixed to the track, serves to engage the lug 12c and hold it against the set screw 16, whereby the pins 14a are held at the minimum angle to the vertical so as to facilitate stripping of the fabric from the pins in the usual manner.

During the movement of the chain link 11 from the loading station L to the stripping station S (that is, after disengagement of lug 12c from cam 17 at the loading station, but before engagement of this lug with cam 17 at the stripping station), the pin carrying lever 12 is free to swing clockwise on its pivot 13 from the full line position of the lever, as shown in Fig. 1. Accordingly, as the chain link 11 moves along the diverging portion of the corresponding rail 10 (Fig. 5), the corresponding pin plate 14 will be raised to about the level of the axis of pivot pin 13, because of the increased weft-wise tension created in the fabric F by the divergence of the opposing rails 10. Thus, the lever 12 will hold the pin plate 14 in approximately the position shown in dotted lines in Fig. 1, wherein the tenter pins 14a diverge at a substantially greater angle from the vertical, that is, at an angle of about 40 as illustrated. This means that the tenter pins 14a now afford a much greater resistance to lifting of the fabric from the pins, as by a greater pressure on the lower surface of the fabric than on its upper surface, as the fabric moves through the dryer. Moreover, any such tendency to lift the fabric F from the pins 14:: results in the pin plate 14 following this upward movement to some extent, by the swinging of lever 12 on its pivot 13. It will be apparent that such further upward movement of pin plate 14, above the horizontal position shown in dotted lines in Fig. l, causes the tenter pins 14a to diverge at a still greater angle from the vertical, thereby further increasing the resistance to upward displacement of the fabric from the pins.

With the construction as described, the fabric F can be impaled upon and stripped from the tenter pins 14a as readily as in pin type tenters of conventional construction, since the earns 17 hold the pins 14a at the minimum angle to the vertical during the impaling and stripping operations. On the other hand, during the travel of the fabric F through the dryer (that is, between the loading station L and stripping station S), the tenter pins 14a are free to swing about the pivot 13 of lever 12 and thereby adjust themselves automatically to the weft-wise tension in the fabric and to any upward or downward movement of the fabric due to unequal pressures on its upper and lower surfaces. The greater the weft-wise tension in the fabric, the greater is the tendency for the lever 12 to move to its horizontal position and for the pins 14a to'assume a greater angle to the vertical so as to increase the resistance to upward displacement of the fabric from the pins. Due to the fact that the pin plate 14 can rise with the fabric above the horizontal position shown in dotted lines in Fig. 1, the fabric is held more securely on the pins than would be the case if the latter were maintained at a fixed angle (40, for example) relative to the vertical.

When the fabric F is subjected to a greater pressure at its upper surface than its lower surface, it will tend to depress the pin plate 14 toward its lower or loading position. This movement, of course, will reduce the angle of divergence of pins Ma from the vertical and thereby reduce the resistance to upward displacement of the fabric from the pins, which may be objectionable in some cases. Accordingly, in such cases it may be desirable to provide supplemental cam means 19 operable on the lever 12 during movement of the chain link through the dryer. As shown in Fig. 1, the supplemental cam means comprise a cam 19 secured to the inner guide plate a by a bracket and engageable with a detent 12d on the lug 12c. The cam 19, of course, extends between the cams 17 at the loading and stripping stations L and S, respectively (Fig. 5). When the lug 12c leaves the cam 1'? at the loading station L, its detent 12d engages a sloping surface 1% at the adjacent end of cam 19 (if the pin plate 14 has not already been raised by the weft-wise tension in fabric F) and is depressed by cam 19 so as to lower the lug 120 from the stop or set screw 16; and for the remainder of the movement of link 11 to the vicinity of cam 17 art the stripping station S, the supplemental cam 19 overlies the detent 12d so as to prevent downward movement of the pin plate 14 to its loading position shown in full lines in Fig. l. The height of the supplemental cam 19 may be such as to prevent downward movement of pin plate 14 below the horizontal position shown in dotted lines in Fig. l. This cam, however, allows the pin plate 1 3 to move upward with fabric F above the horizontal position, as previously described.

It will be understood that the two endless chains made up of inter-connected links it are suitably guided to move in closed paths having upper sections on the tracks 10, and are driven in the usual manner so that their upper sections move along the tracks from loading station L to stripping station S While the lower sections undergo return movement to loading station L, as is conventional in the art.

It will also be understood that when the lever 12 of each link 11 is held in its fabric-loading or fabric-stripping position against stop 16, by one of the cams 17, the position of the tenter pins 14a relative to the vertical may be otherwise than as shown in the drawings. For example, the pins 14a may be set to extend straight upward (zero angle to the vertical) when the lever 12 is in this stopped position, or to extend at any other desired minimum angle compatible with the usual operations of impaling the fabric on and stripping it from the pins. Whatever this minimum angle may be, the inner portion of lever 12 will swing upward under weft-Wise tension in fabric F upon release of the lever by cam 17, due to the location of pin plate 14 below the horizontal level of lever axis 13 when the lever is held against stop 16; and this upward swinging causes the pins to assume a greater angle to the vertical while diverging from the pins of the opposing chain, so as to hold the fabric more securely on the pins.

Iclaim:

1. In a tenter of the pin type having a pair of tracks, and endless tenter chains including inter-connected links movable on the tracks for drawing a fabric therealong from a fabric-loading station to a fabric-stripping station, the combination of a lever pivoted on each link of at least one chain for swinging movement about an axis substantially parallel to the corresponding track, the lever extending inward from said axis toward the opposing chain, tenter pins extending upward from the inner portion of the lever and adapted to pierce the selvage of the fabric, a stop engageable with the lever to limit downward movement of the pins relative to the link, the lever when engaged with said stop being in a fabric loading position wherein the upwardly extending pins are at a minimum angle to the vertical and have their base portions located below the horizontal level of the lever axis, the lever being swingable from the stop whereby the upwardly extending pins are raised relative to said axis and assume a greater angle to the vertical, and cam means fixed relative to the corresponding track and engageable with the lever to hold the same against said stop.

2. The combination according to claim 1, comprising also an arm on the link extending inward therefrom toward the opposing chain, the lever being pivoted on the inner portion of said arm.

3. The combination according to claim 1, comprising also an arm on the link extending inward therefrom toward the opposing chain, the lever being pivoted on the inner portion of said arm, the stop being located on said arm.

4. The combination according to claim 1, comprising also an arm on the link extending inward therefrom toward the opposing chain, the lever being pivoted on the inner portion of said arm, the stop being adjustably mounted on said arm.

5. The combination according to claim 1, comprising also a pin plate mounted on said inner portion of the lever, the tenter pins being secured to the pin plate.

6. The combination according to claim 1, comprising also supplemental cam means fixed relative to the corresponding track between said stations and engageable with the lever to hold the lever away from said stop.

7. The combination according to claim 1, comprising also supplemental cam means fixed relative to the corresponding track between said stations and engageable with the lever to hold the lever away from said stop, said first cam means including a cam at each of said stations.

8. The combination of a chain link for tenters of the pin type, a lever pivoted on the link for swinging movement about an axis extending lengthwise of the link, the lever having a portion extending laterally from the link and the lever axis, tenter pins extending upward from said lateral portion of the lever and adapted to pierce the selvage of a fabric, and a stop on the link engageable with the lever to limit downward movement of the pins relative to the link, the lever when engaged with said stop being in a fabric loading position wherein the pins extend upward at a minimum angle to the vertical, the base portions of the tenter pins being located below the horizontal level of said axis when the lever is engaged with the stop, the lever being swingable from the stop whereby the pins are raised relative said axis and extend upward at a greater angle to the vertical and toward the link.

9. The combination according to claim 8, comprising also an arm on the link extending laterally therefrom, the lever being pivoted on the arm.

10. The combination according to claim 8, comprising also an arm on the link extending laterally therefrom, the lever being pivoted on the arm, said stop being mounted on the arm.

References Cited in the file of this patent FOREIGN PATENTS Germany Feb. 5, 1913 

